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Date: Thu, 26 Mar 2020 16:31:15 +0300
From: Konstantin Osipov <kostja.osipov@gmail.com>
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Subject: Re: [Tarantool-patches] [PATCH 3/6] iproto: Add negotiation phase
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To: Kirill Yukhin <kyukhin@tarantool.org>, lvasiliev <lvasiliev@tarantool.org>, alexander.turenko@tarantool.org, tarantool-patches@dev.tarantool.org

* Konstantin Osipov <kostja.osipov@gmail.com> [20/03/26 16:19]:
> A vshard based cluster with 20 router nodes and 20 storage nodes,
> 32 core each, will have 20*32*32*16 connections.

These are only internal connections maintained by vshard. 

Replication adds miniscule 32*20*2 connection to that.

Any monitoring will be likely establishing a new connection for
every monitoring request, 32*40 connections per second.

Any quality of service feature, like separating oltp and
analytical traffic, could easily require doubling it, since all
prioritized work has to use its own transport infrastructure. 

Any network partitioning event will lead to avalanche like
re-establishment of these connections. 

One can ignore performance concerns, of course, given there has
been a foundation of scrupulous accounting for every bit and every
CPU cycle, but not very long. 

> A 20-40 node cluster is not big by any means.
> 
> -- 
> Konstantin Osipov, Moscow, Russia

-- 
Konstantin Osipov, Moscow, Russia